Hydrogenation of hydrocarbons



Patented Apr.'1 1,'l933 NITED STATES PATENT OFFICE WILLIAM S. CALCOT'I', O1 IENNS GROVE, NEW JERSEY, ALBERT S. CARTER, OF 1 WILMINGTON, DELAWARE, AND FREDERICK B. DOWNIN G, OF OARNEYS POINT, NEW JERSEY, AS SIGNORS TO E. I. DU PON'I' DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE .10 Drawing.

HYDBOGENATION' or maooanaons This invention relates to the hydrogenation of unsaturated com 'ounds and particularly to the catalytic hy rogenation of polymerizable acetylene polymers.

Prior art It is known that bypassing acetylene intd a mixture of ammonium chloride, water, cuprous chloride and copper powder of suitable proportions and under'proper conditions, unsaturated hydrocarbons of higher molecular weight are formed." These hydrocarbons may be separated by distillation from stituent is called divinylacetylene and most probably has the empirical formula C l-I6.

Others formed in appreciable proportions,

' must be employed. One successful methodvelopment of com which may be mentioned, are believed to have the formulae (1 H and 0 H These prod nets in turn may be roughly separated by distillation. If t a It is also known that the crudemixture, any oneof its constituents or mixtures of the various constituents may be polymerized in various ways, for instance, by aging at ordi-. nary temperatures. The polymerization is greatly accelerated. at elevated temperatures, and is known to take place either in the presence of oxygen or inert gases, as nitrogen. In the presence of oxygen, the pol eri zing material will absorb oxygen wit the deunds having explosive properties. There ore, it is desired to carry out the polymerization in an oxygen I environment and at the same time produce a material free from chemically combined oxygen'some method for inhibiting oxidation already disclosed is to incorporate into the material to be polymerized a substance which 'will prevent oxygen absorption. I

the polymerization proceeds regardless ofthe methodemployed, the material passes successively-to an oily, then to a gelatinous,

then to a resinous mass, and finally yields a hard, brittle resinous material having un- 0 Application filed Iarch .24, 1930. Serial No. 438,658;

usual resistance to the action of water and to organic solvents. The oily roduct which is first formed is largely solu 1e in alcohol and acetone ;'the gelatlnous body next formed is largely soluble in acetone but only partially soluble in alcohol; the resinous modification is substantially insoluble in alcohol and is to a slight extent soluble in acetone; the final,-hard, brittle polymers are substantially insoluble in both alcohol and acetone. These successive polymerization products apparently consist of a group of compounds in various stages of polymerization and they may be only roughly separated by dissolving. They may be successively separated by distillation.

If the polymerization is stopped in the .initial stages, the oily liquid polymer obtained may be separated from the volatile unpolymerized material by distillation. The resultant residue is a non-volatile substance having thegeneral properties of a bodied drying oil. It has been shown that this drying oil may be used in tlie manufacture of paints or other coating compositions. It may be mixed with the solvents, pigments, fillers, etc.,' commonly employed in the preparation of coating compositions.

y The example following illustrates the preparation from acetylene'of the polymerizable polymerby the known method referred to above.

. Ewample A v 945 parts by weight of ammonium chloride,

parts by weight of water, 2850 parts by weight of cuprous chloride, and 100 parts by weight of copper powder, are mixed and this mixture thoroughly agitated while passing into it acetylene gas. When the. reaction slows up, as shown by a decrease in the rate of absorption of acetylene, the operation-is discontinued, and the highly unsaturated hydrocarbon product formed is obtained by distillation, which is stopped when the condensed hydrocarbon .is mixed with, much water. The water is separated and returned to the reaction mass which, after cooling, is ready for the absorption of morela'cetylene. It is preferable, although not essential, to keep the reaction temperature at approximately 25 C. by suitable cooling of the reaction, mass. As already stated, the resultant material contains a number of polymersthe most abundant of which isbelieved to be divinylacetylene and to have the formula 1000 grams of' pure divinylacetylene obtained from the product of Example A by distillation is boiled at atmospheric pressure and in the presence of air for four hours in a vessel provided with a condenser for the return of the condensed vapors to the rea ction. The temperature of the-boiling liquid is between 89 and 90 C. At the end of four hours the unchanged divinylacetylene is dis-.

tilled oil under reduced pressure. There remains, in 12 to 18% yield, a viscous nonvolatile residue having the general properof the polymerized ties of a bodied drying oil and consistingivinylacetylene. The above examples, it will be understood, merely illustrate the preparation of the a1 ready known vmaterials and are not a part of and that the polymerization, insteadof the present invention. It will be understood that any one of the first-step polymers or a mixture thereof may be polymerized similarly to the divinylacetylene of Exam 1e B mg discontinued at the oily stage as described in Example B, may be continued to any of the --successive stages of' partial polymerization .the characteristic behavior of the polymeriz-' described above or to obtain a solid polymer as the final product.

Object of the invention 7 Owing to their high degree of unsaturation,

'fable acetylene olymers, as prepared by the methods descri ed above,,is to rapidly absorb oxygen and also to undergo further polymerization. It is the object of this invention to utilize the .high degree of unsaturation to form from such polymers, other than by polymerization alone, -more stable compounds, which com ounds will have a decreased tendency to oxi 'ze and polymerize and will themselves be valuable or will constitute valuable intermediates for the preparation of numerous, useful and novel compounds.

' Description of invention These objects are accomplished by decreasin the .high unsaturation of the acetylene p0 ymer molecule by adding on hydrogen through the agency of hydrogen 'gas with the aid of a catalyst. In this manner, compounds are produced which contain more hydrogen and as a result are less unsaturated, showing a decreased tendency to polymerize and absorb oxygen, chlorine, bromine, etc.

We have found that all of the acetylene o1 mers and pol merized acet lene olyiiiel s described aboi e (see Prior rt) will react with hydrogen under suitable conditions, with the possible exception of the substantially completely polymerized hard brittle soli polymer. The less highly polymerized solid polymers of the semi-plastic type, however, react normally.

The product of this hydrogenation .is a,

mixture of saturated and unsaturated hydrocarbons, the average molecular weight of which is dependent upon the particular acetylene polymers started with and the percentage composition is dependent upon the catalyst, the tem erature and pressure, and the quantity of ydrogen added. Thus, if

one starts with the acetylene polymer thought to be divinylacetylene, O I-I the reduced products will contain some or all of the followin hexane, hexene, hexadiene, hexatriene, et ylvinylacetyleneand diethylacetylene; if the starting material be the tetranier of acetylene, C H the products will contain octane and a series of unsaturated hydrocarbons of eight carbon atoms. In each of these cases, however, the relative quantities of the constituent products is determined by the catalyst, temperature, pressure, and quantity of hydrogen absorbed.

The invention will be readily understood from consideration of the followin examples which of course are furnished y way of illustration. 4

Emample I 780 parts (by weight) of the purified acetylene polymer as described under A- (above) and. thought to be divinylacetylene,

' are added to a solution containing 5000 parts of water, 5000 parts'of ethyl alcohol, 5 parts of gelatine and colloidal all'adium repared by reducing. 2= parts of dCl .2H g. This reaction mixture is held at'room temperature under an atmosphere of hydrogen while violentl a ita-ted until approximately 80 f hy parts 0 rogen have been absorbed. The mixture'is then steam distilled and the product purified by known methods giving a saturated oil which will not absorb bromine nor oxygen, having a boiling point of 68-7 0 0., a

molecular weight of 86 and a density of 0.66

at 20 indicating it to be probablym-hexane,

' Eagample l I 100 parts of the acetylene polymer used in Example 1 addedto an equal quantity of sulfur-free decahydronaphthalene together with 1 part'of platinum oxide,jobtained by I chloroplatinic acid with sodium nitrate and washing the i ited oxide .free of sodium is placed under ydrogen at 2.to 3 atmospheres pressure and shaken until hydrogen is no longer absorbed. The product, after rectification, is identical with that obtained in Example I. The product may be removed from the catalyst by decantation and the catalyst used again.

Example III N100 parts of the acetylene polymer thought to be the tetramer G H is hydrogenated in the manner of Example II and the resulting product no longer absorbs bromine, has a molecular weight of 114, a density of 0.71 at 15 (3., a boiling point of 125 and is apparently octane. 1

Example IV V A .mixture containing one volume of hydrogen and one volume of the acetylene polymer thought to be vinyl acetylene (C H are passed over an active nickel catalyst at 80-150 C. at a rate such that the hydrogen is completely absorbed. The gaseous products maybe collected in a suitable freezing mixture as a water white oil boilingfrom- 5 to +10 C. thought to be a mixture of butane, butylene; butadiene and ethyla cetylene.

Example V 100 parts of the polymerized acetylene polymers of Example B .characterized as the viscous non-volatile oil is dissolved in two volumes of sulfur-free benzene containing 1 part of platinum catalyst used in Example II, is placed'under 3 to 10 atmospheres pressure of hydrogen and violently a itated at a temperature between 25 to 100 until the hydrogen absorption is complete. Approximately 4.74.8 parts of hydrogen are ab.- sorbed giving, after removal of the benzene, a product similar to the original pol merized acetylene polymer, but showing a ecreased tendency to absorb oxygen and bromine.

Emample VI phere of nitrogen, then poured into 3 volumes erties.

of alcohol precipitating a resinous semisolid product. 100 partsof this resinous solid are dissolved in benzene and hydrogenated as in Example V, giving upon removal of the solvent, a waxyamor'phous product which will slowly absorb oxygen and which is still un saturated as indicated by its absorption of bromine, but whichresembles more nearly a paraflin-like substance in its physical prop- Example VII IQQparts of the acetylene polymer thoughtby well. known methods.

equal volume of. acetone and 5 parts of a reduced nickel catalyst supported onkieselguhr and containing about 40% nickel are added. This catalyst may be prepared by 4 precipitating nickel hydroxide on kleselguhr 7 and igniting in an atmosphere of hydrogen The mixture isplaced under 2 to'10 atmospheres of hydrogen pressure and heated to 100 C.-with vioent agitation. When 2.5 parts of hydrogen have been absorbed, the product is removed and found to be different from the original material in that it absorbs oxygen more slowly and is less unsaturated with respect to bromine absorption. If the hydrogen absorption be allowed to continue, 5.5 or more parts may be added, progressively decreasoxygen and bromine. Theproduct obtained by this partial hydrogenation contains prac-: tically no hexane or hexene but is believed to contain hexatriene (boiling 7 580 C.) hexadienes, ethylvinylacetylene and diethylacetylene together with some unreduced acetylene polymers. This-mixture may be separated by nown methods of fractionation or may be used directly. It and some of its constituent hydrocarbon members have been found topossess valuable application as resin forming materials, intermediates for the preparationof alcohols, glycols, halogencompounds and their derivatives.

/ a Example VIII parts of the crude acetylene polymers 100 prepared as described under Example A (above) are dissolved in an equal volume of acetone and hydrogenated as described in Example VII. The product is similar to that obtained in the prevlous example except that it contains unsaturated compoundscontain- .ing 4 and 8 carbon atoms in addition to those containing 6 carbon atoms. It may be sepa-- rated by known methods-of fractionationinto its constituent members.

It will be evident from the abovleexamples that any desired amount of hydrogen up to approximately 10% of the starting weight of polymer may be added-with a sultable catalyst. This reduction appearsto take place Ill in steps, therefore a different ratio-of prod 'ucts results with change in the quantity of hydrogen absorbed. It is therefore possible to obtain high yields of hydrocarbons which are less unsaturated than the original ac'ety- 12C lene polymer and varying in saturation to, the completel saturated paraflin, as desired. The degree 0 saturation will, of course, in a given case, be determined by the contemplated use. 12:

Obviously the reaction must be carried out I in the absence of air and under non-oxidizing conditions generally.

It will be seen from the examples'thatthese acetylene polymers, which. are ordinarily in acetylene polymer and ert toward gaseous hydrogen, will absorb it yvith rapidity in the presence of suitable cataysts.

The polymer may or may not be in solution as desired, or it may be mixed with a solvent in which it is ,only partially .soluble. The solvent must be one which will not poison thecatalyst nor react with any of the constituents under the conditions of the operation. Various solvents frequently affect the velocity of the hydrogen absorption thus permitting its control without having a detrimental eiiect upon the catalyst. The following solvents have been found valuable: acetic acid, methyl alcohol, ethyl alcohol, propyl'alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, acetone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl butyrate, ethyl butyrate, butyl butyrate, other esters of low molecular Weight, mixtures of water with methyl and ethyl alcohols, acetone or acetic acid, benzene toluene, xylene, tetrahydronaphthalene, decahydronaphth'alene, cyclohexane, cyclohexanol, methylcyclohexane, pentane, hexane, heptane, octane, and other saturated hydrocarbons. Some solvents which are suitable under one set of conditions may be themselves reduced and unsuited underother conditions, thus with the use of a nickel catalyst at low temperature and pressure, acetone may be used, whereas at higher temperature it is reduced to isopropyl alcohol. This simultaneous reduction does not pre-. vent the reduction of the acetylene polymer if suflicient hydrogen is present, but is generally best avoided in order to eliminate the loss of hydrogen.

- When reduction is carried out in the liquid phase, either with or without a solvent, good agitation is necessary to getrapid reaction. A typeof agitation WhlCh is adapted to bring in contact the h meta lic catalyst is pre erred.

We have further found that the hydro- .genation may be carried out in the vapor re of the vaporized the desired amount of hydrogen through thecatalyst. The catalyst must be mounted in p a manner to allow temperature control, for after the reaction is started, which may decompose the reaction mixture. To aid in controlling the vapor phase reaction, both with 're ard to temperature and the quantity of hy rogen added it is frequently advantageous to add. an inert gas to the vapor mixture, such as nitrogen, dry steam, ethyl alcohol vapor, carbon dioxide, or the like.

phase, by passing a mixt Catal sts composed of metals of the first and eig th groups either alone o'rin comb1-' nation with other metals or, inert supports have been foun% useful for this hydrogenation; for examp a, reduced platinum black.

drogen gas and the presence of .a large quantity of heat isevolvedthe absence of air, with hydrogen,

'for the reaction are dependent upon the activity of the catalyst, thus with colloidal palladium, active hydrogen absorption will result at room' temperature or lower and at reduced pressure, whereas the more common types of nickel catalyst require a temperature of over C. and pressure of 2 atmospheres or more The vapor phase reduction is conveniently carried out at 100- 150? C. and atmospheric pressure. The ractical limits of temperature may be thereore set at from 15 to 150 C., although slightly higher or lower temperatures may be employed.

It will be understood that the resulting products are mixtures of complex constitu: tion and that it is impossible to state what is their exact chemical constitution. Theunsaturated constituents of such mixtures will, of course, still polymerize and absorb oxygen but at a relatively lower rate than the original polymer. The hydrogenation also tends to lower the specific gravity and boiling point of the material treated. I

As many apparent and widely different embodiments of this invention may be made without departing from the spirit thereof, it is to be understood that we do not limit ourselves to the foregoing examples or description except asindicated in the following claims.

We claim:

1. The process which comprises reacting under nonoxidizing conditions a polymeriz- I able nonbenzenoid acetylene polymer, in the presence of a hydrogenation catalyst, with hydrogen.

2. The process which comprises reacting under nonoxidizing conditions a polymerizable nonbenzen'oid acetylene polymer, in the a hydrogenation catalystand at a temperature between 15 and 150 0., with hydrogen.

3. The process which comprises reacting under nonoxidizing conditions a polymerizable nonbenzenoid acetylene polymer, in the presence of a hydrogenation catalyst and'in the absence of air, with hydrogen;

v .4. The process which comprises reacting under nonoxidizing conditions a polymerizable nonbenzenoid acetylene polymer, in the presence of a hydrogenation catalyst and sai polymer being dissolved in a solvent.

5. The process which comprises reacting under nonoxidizing conditions a polymerizable nonbenzenoid polymer of acetylene with hydrogen. in the presence of a metal of the I class consisting of the first and eighth groups- 1 0 6. The process which comprises agitating, at between and 150 0., a polymerizable nonbenzenoid polymer of acetylene in the presence of an atmosphere of hydrogen, a

ydrogenation catalyst and a neutral sol-' vent until up to 10% by weight of hydrogen as compared to the original weight of the polymer has been absorbed.

- 7. The process which comprises reacting under nonoxidizing conditions divinylacetylene, in the presence of a hydrogenation catalyst, with hydrogen.

8. The process which comprises reacting under nonoxidizing conditions divinylacetyagitating violently to effect the absorption lene, in the presence of. a hydrogenation catalyst and in the absence of air, with hydrogen.

9. The process which comprises agitating, at between 15 and 150 (1., divinylacetylene in the presence of an atmosphere of hydrogen, a hydrogenation catalyst and a neutral solvent until up to 10% by weight of hydrogen as compared to the original weight of the polymer has been absorbed.

10. The process which comprises mixing 100 parts of divinylacetylene with a substantially equal volume of a neutral solvent and a hydrogenation, catalyst, placing the mixture under from 2 to 10 atmospheres of hy drogen pressure, heating to 100 0., and

of hydrogen.

11. The process which comprises agitating, at between 15 and 150 C., a polymerizable nonbenzenoid polymer of acetylene in the presence of an atmosphere of hydrogen,

a nickel catalyst and a neutral solvent until up to 10% by weight of hydrogen-as compared to the original weight of the polymer has been absorbed.

12. The process which comprises agitating, at between 15 and 150 (1, divinylacetylene in .the presence of an atmosphere of hydrogen, aneutral solvent and a catalyst comprising reduced nickel untilup to 10% by weight of hydrogen as. compared to the original weight of 'the'polymer has been absorbed. I

13. The process which comprises mixing 100 parts of divinylacetylene with a substan-' tially equal volume of a neutral solvent and 5 parts of a catalyst of reduced nickel on kieselguhr, placing the mixture under from 2 to 10 atmospheres of hydrogen pressure, heating to 70-100" 0., and agitating violently to effect the absorptionof hydrogen.

14. A mixture of saturated and unsaturated hydrocarbons obtainable by hydrogenating a polymerizable nonbenzenoid acetylene polymer. I

15. A mixture of saturated and unsaturated hydrocarbons obtainable by reacting under conditions a 'polymerizable non-oxidizin nonbenzenoi acetylene polymer, in the pres hydrocarbons obtainable by agitating, at betW88I115 and 150 (3., a polymerizable nonbenzenoid olymer of acetylene in the presence of an atmosphere of hydrogen, a hydrogenation catalyst and a neutral solvent until up to 10% by weight of hydrogen as compared to the original weight of the polymer has been absorbed.

18. A mixture of saturated and unsaturated hydrocarbons obtainable by reacting under non-oxidizing conditions a polymerizable nonbenzenoid acetylene polymer, in the pres-' ence of a hydrogenation catalyst, with hydrogen.

19. A mixture containing saturated and unsaturated hydrocarbons of 6 carbon atoms and obtainable by mixing parts of divinylactylene with a substantially equal volume of .a neutral solvent and a hydrogenation catalyst, placing the mixture under from 2 to 10 atmospheres of hydrogen pressure, heating to 7 O100 0., and agitating violently to efl'ect the hydrogenation of the polymer.

In testimony whereof we afiix our signatures.

WILLIAM S. CALCOTT. ALBERT S. CARTER.

FREDERICK B. DOVYNING. 

